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im in the process of installing their 3" tail pipe section, having alot difficulties getting things to line up. i emailed IRO with a picutre to ensure i got the correct part, which they confirmed i did, however they mentioned its a tight fit and that i need to space out my sway bars 1". The exhaust also routes over the track AND sway bar (stock goes under the sway)

the site neglects to inform you on the exhaust page that you should/need a sway bar spacer kit. had i known this ahead of time, i may have purchased the kit at the overpriced $30. instead im building my own for $10. the 4 longer bolts needed are m10x50 Coarse thread, and metal spacer block is approx 2" W x 4.25" L x 1" H (you need 2 blocks). drill 4 holes and bolt it up.

It's 3" from the y-merge back, sounds good and it's QUIET (which seems hard to do after camming the thing). From behind the Jeep, it's just a little louder than stock (barely). From next to the Jeep at idle, it's quieter than stock. From inside, it's also quieter than stock (at idle, cruise and WOT).

At WOT, it's downright quiet, even with the windows down. It's got a nice tone, but in terms of volume level, it's kinda like driving a V8 Camry. Pretty much perfect for a sleeper build, as nobody would really notice that it isn't stock unless they heard it side by side with a stock niner

So shorty headers don't look like to bad a way to go, if you can get them to fit. Anyways thought you guys might think this was interesting. I'm going to be ordering a weld up header kit this week some time. I'm going to see if I can get away with long tubes (I've been cleaning up the engine bay, getting rid of some stuff I don't need). If not I'll just have a set of shorties with 1.75" primary tubes for the 408. I think a motor this big needs the bigger primary tubes, the shorty headers like the Eddy ones with the 1.625" primarys are OK for a 318 or 360 but are just going to be restrictive for a 390 or a 408.

... I'm going to see if I can get away with long tubes (I've been cleaning up the engine bay, getting rid of some stuff I don't need). ...

Originally Posted by comptiger5000

Long tubes are possible, but they might have to be custom. I think all of the off the shelf ones are shaped wrong and won't fit a ZJ (will hit either UCAs, the body, starter, etc.)

Just something to keep in mind...

I saw someone with a Chevy motored drag XJ build. His front suspension was modded so that his upper and lower CAs where Wye'd together off (I believe) just the lower CA. I think that's somewhat similar to some of the offroad setups? - but of course these were done to different dimensions.

I don't know how that would affect handling, but if it was a dedicated drag build I guess one could make some sacrifices in that area.

Just mentioned it because it could possibly allow some different or better clearance in that area. Maybe.

I saw someone with a Chevy motored drag XJ build. His front suspension was modded so that his upper and lower CAs where Wye'd together off (I believe) just the lower CA. I think that's somewhat similar to some of the offroad setups? - but of course these were done to different dimensions.

I don't know how that would affect handling, but if it was a dedicated drag build I guess one could make some sacrifices in that area.

Just mentioned it because it could possibly allow some different or better clearance in that area. Maybe.

Radius arm setup, doubt it would be possible in a short arm situation.

Yesterday I hit a lost tire on the highway, it broke my downpipe on the ZJ 5.9

I would like to replace downpipe and full exhaust.

I don't have money for DT headers, so I would like to get fab a custom downpipe into a custom 3'' exhaust. What is best downpipe size ? I can get a flowmaster Y pipe 2.5'' inlets and 3'' outet for cheap where I live. Is this a good Y pipe ? 2.5'' downpipes can fit onto stock exhaust manifolds ?

I just threw a 3" Walker Soundfx muffler on my white one. Had to fix the exhaust to make it drivable...

Exhaust was cracked on the outlet side of the flange, then the rest of it rusted and fell apart, lol - so I took the opportunity to yank the DTs and go back to stock mannies and downpipe from my white parts niner. That's had a 3" cat on it already so I had to match that.

Except for the 3" stuff this one is stock (and/or being returned to stock) and I'm just DDing it before it gets sold, so I was looking for something reasonably quiet so I don't piss off the neighbors when I come home late at night.

That said - it's pretty decent for that. Reasonably quiet and I can get in my driveway without feeling like an Ahole

Mine is really quiet with the current setup. Similar to stock when driving gently, a little quieter at idle and has some bark when you get on it. The setup is DT headers, high flow spun body cat, 3" Vibrant Ultra-quiet resonator and Magnaflow 12579 muffler.

As far as the video, around 2:20 there's some nice downshift crackle and there's a WOT pull through 1st around 4:00.

Mine is really quiet with the current setup. Similar to stock when driving gently, a little quieter at idle and has some bark when you get on it. The setup is DT headers, high flow spun body cat, 3" Vibrant Ultra-quiet resonator and Magnaflow 12579 muffler.

No, the resonator is between the cat and muffler. The DT y-pipe ends far enough forward that I was able to fit the cat forward of the crossmember with the resonator where the cat used to be.

At some point this summer, I'm going to be working with a friend to re-do the exhaust to a 3.5" setup. It'll involve custom making a y-pipe, hopefully still being able to fit a cat forward of the crossmember and then I'm planning on running a 3.5" Dynomax Ultraflo Welded feeding into a Magnaflow 12909 (should be similar volume to my current setup). And then we get to make a 3.5" tailpipe to fit this thing...

I guess DT headers is the difference- not much room with Thorley's. I wouldn't mind toning mine down slightly, but didn't want to put anything behind the axle.
Sounds like a good setup you have planned this summer. When I do my heads/cam next summer my plan was to go dual shorties, which would require modifying the driver side Thorley to dump left. Should have done that in the first place, but I was in too much of a rush to get it done.
Wish I had an exhaust buddy... Stan's Headers is the only exhaust place I trust around Seattle, and they cost a fortune. Took my 3" Kolak somewhere else the first time and they botched the tailpipe so bad I had to buy the tailpipe again and took it to Stan's A good deal is what you get, not what you pay!

Omm... DT... Doug Thorley... same thing? After all this time it never clicked. Never cared about DT's because I had Thorleys!
So- don't see how you fit the CAT forward of the cross member, unless you have a freakishly stubby CAT. There's less than 7" from my Y-pipe to cross member.

DTs are Thorleys, lol. The cat is a fairly short spun body unit, not one of the standard cat-shaped ones. The input has a flange added to it that bolts right to the y-pipe output flange and the output of the cat is about a 1/2" forward of the crossmember. The cat is this guy: http://www.magnaflow.com/02catalytic...versal=99959HM

When I re-do the setup, I'm contemplating whether it would be worth pulling the driver's side Thorley out, modifying the output to dump at a different angle and then getting it re-coated. Being able to get the y-pipe tucked up tighter would be nice, but I probably won't bother (it'll have a skid plate over that area before the next time it gets wheeled).

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